Ags x 10 kn

The static tensile test was carried out according to (PN-EN ISO 527—type 1:2012) [29 ] on an MTS Criterion Model 43 universal testing machine (MTS System Corp., Eden Prairie, MN, USA) with an MTS axial extensometer. The measuring base was set to 100 mm, and the test speed was equal to 5 mm/min. The three-point flexural test (PN-EN ISO 178:2011) [30 ] was carried out using a Shimadzu AGS-X 10 kN (Kyoto, Japan) testing machine with TRAPEZIUM-X software, https://www.shimadzu.com/an/products/materials-testing/uni-ttm-software/trapezium-x/index.html. The distance between supports was set to 64 mm; test speed was 10 mm/min. The Charpy impact test was performed using a Zwick/Roell HIT5.5P hammer (Ulm, Germany) according to PN-EN ISO 179-1:2010 [31 ]. Measurements were examined on unnotched specimens.
Mechanical hysteresis loops were obtained by dynamic testing on a Shimadzu AGS-X 10 kN (Kyoto, Japan) testing machine with TRAPEZIUM-X software for dissipation energy analysis. The samples were subjected to cyclic loading and unloading at 10 mm/min speed. The applied force corresponded to 60% of the maximum force needed to break the sample, determined during the tensile test.

For the tensile testing, ISO 527-2 [35 ] type 5 A specimens were obtained by injection molding with the mini injection machine HAAKE MiniJet II (Thermo Fisher Scientific, Waltham, MA, USA). The injection molding processing conditions of the virgin and recycled PP specimens are shown in Table 2.
The tensile tests were conducted on the machine Shimadzu AGS-X-10kN (Shimadzu Scientific Instruments (SSI), Columbia, MD, USA) following the standard ISO 527-1 [36 ]. These tests were executed at ambient temperature in two steps. First, the specimens were pulled with a tensile rate of 1 mm/min to obtain values for calculating the Young modulus. In the second stage, a tensile rate of 50 mm/min was applied and maintained until the specimens ruptured. The data from this second test was used to determine the yield stress (σ_y) and strain (ε_y), and tensile strength (σ_u) and strain at break (ε_b). It should be noted that the latter is especially relevant for the polymer degradation assessment because of this property’s extraordinary sensitivity to any structural change [37 (link)]. For each PP batch, five specimens were tested.

The design was evaluated by recreating the bench test setup of Barkholt et al. [16 (link)]. With a GW in place, the tip was pressed against a plate with a hole slightly larger than the GW (0.36 mm). The tip was clamped into the universal testing machine Shimadzu AGS-X 10 kN (Shimadzu Corporation, Kyoto, Japan). The force required to compress the tip by 0.5 mm was recorded using a 200 N load cell with an accuracy of the measured value of ± 0.5% in the range of 0.4–200 N. Below 0.4 N, the accuracy of the measured value is reduced to ± 1%. While the GW can pass through the hole, the tip gets pressed against the plate. The damage of the tip was assessed by measuring the diameter before and after the test, respectively.